Oxford dons decided not to be hustled and bustled about by it in the 19th century — and instead went on using their old Oxford Time when the rest of the nation accepted the introduction of Greenwich Mean Time.

Even today Oxford’s largest college, Christ Church, operates five minutes behind everyone else. Great Tom, the huge bell weighing more than seven tons and with a diameter of almost seven feet, still rings out its unheeded curfew 101 times every evening at five past nine — or, as those old slow coaches on the other side of the college gates would call it, nine o’clock; even though Greenwich Mean Time was introduced 160 years ago in 1852.

Doubtless Great Tom’s deep tones will resonate round the city in June to mark The Queen’s diamond jubilee, just as they did in 1897 when her great-great grandmother, Victoria, celebrated hers. On that occasion, two new bells were also added to the ten already hanging in the cathedral).

Great Tom, the very embodiment of the timeless voice of Oxford’s soul, has been expressing joy (and sorrow, too, with clapper muffled) at royal and national occasions since Christ Church was founded in 1546; and perhaps even longer, since before that it hung in the abbey of Osney which, for five years, was Oxford Cathedral.

But in that year, college chief carpenter John Wesburn undertook the heavy responsibility of removing the eight bells — called Hautclere, Douce, Clement, Austin, Marie, Gabriel, John and, biggest of all, Great Tom — from the tower of poor old doomed Osney, and reinstalling them in the college chapel that had just been upgraded to cathedral status. The bells were moved by a carter called Mr Willoughby of Eynsham.

I gather most of this detailed knowledge from a new book by Christ Church archivist Judith Curthoys (The Cardinal’s College, Profile Books, £40). Talk about being summoned by bells (in Betjeman’s phrase): the bells ordered the daily life of Christ Church to such an extent that already by 1583 new machinery, such as bell wheels, were needed, along with new clappers.

During the reign of the Catholic Mary Tudor (1553-1558) Great Tom underwent a gender change and was renamed Mary — an event that was then conveniently forgotten about during the reign of Protestant Elizabeth,when he/she/it again became Tom. But in 1612 the bell was recast, possibly to get rid of a ‘Papist’ inscription.

By 1680 there were 11 bells in the cathedral tower, including Great Tom. In that year ten were rehung. But Great Tom was set aside and installed, 14 years later, in Wren’s Tom Tower over the college gate where it still resides. It ‘spoke’ loud and clear on Restoration Day, May 29, 1694 (commemorating the date Charles II was restored to the throne in 1660).

But why does Great Tom ring out 101 times every evening? Answer: it tolls once for each of the 100 students (the equivalent of fellows in other colleges) on the original 1546 foundation, and once more for the Studentship created by the Thurston bequest. William Thurston left £800 in 1664 to “the King’s College, Oxford”, so called. Brasenose and Oriel reckoned he meant them, but the Archbishop of Canterbury, sitting in the Court of Arches, awarded the money to Christ Church.

As for Christ Church living along five minutes behind the rest of us, slowness in teachers was something the Mock Turtle knew all about. As he explained to Alice: “We called him Tortoise because he taught us, really you are dull.”

The Mock Turtle, of course, was himself created by Lewis Carroll (Christ Church mathematics lecturer Charles Lutwidge Dodgson) who, 150 years ago this year, first told Alice of her Adventures in Wonderland on that Golden Afternoon of July 4, 1862. Perhaps Carroll had Great Tom in mind when he described the Lion “speaking in a deep hollow tone that sounded like the tolling of a great bell”.